Approximately 1 out of every 5 Americans is infected with herpes simplex virus type 2 (HSV-2). Localized genital infection by HSV-2 results in painful recurring genital lesions while disseminated infection can involve multiple visceral organs and lethal encephalitis. We have developed a new heterologous immunization protocol composed of a DNA vaccine followed by a protein-liposome boost. This protocol induces robust serum IgG antigen-specific high avidity antibodies, a T helper type 1 (Thl)-biased immune response, and antigen-specific cytotoxic T lymphocytes (CTLs). Furthermore, mucosal IgA and IgG responses are also elicited when the boost is delivered intranasally. We hypothesize that this vaccine delivery platform is an ideal protocol for eliciting protection from pathogens which invade at mucosal surfaces. To test this hypothesis, we will use this protocol to develop an HSV-2 vaccine. In Phase 1, we will measure humoral and cell mediated immune responses specific for HSV-2 antigen after immunization with the heterologous immunization regimen. We will then determine whether the vaccine is efficacious by challenging mice intravaginally with HSV-2. Finally, we will perform experiments to test the longevity of protective immune responses generated by the vaccine. In Phase 2, we will characterize the mucosal immune responses generated by heterologous immunization and extend these studies to other animal models. The end result of these experiments will be the establishment of a novel vaccine design and the development of a vaccine for HSV-2. This vaccine would clearly have an impact on the greater than $1.6 billion spent annually on direct medical costs associated with HSV-2. The Public Health Service (PHS) has recognized the significant public health issues caused by herpes simplex virus. The PHS publication, "Healthy People 2010", has set sexually transmitted diseases as a national priority with a goal to reduce the number of adults infected with human papilloma virus and HSV-2. [unreadable] [unreadable] [unreadable]